OBSERVATIONS ON THE MICROFLORA OF MINCED CHICKEN MEAT IRRADIATED WITH 4 MeV CATHODE RAYS

Abstract

SUMMARY: Experiments are described in which minced chicken meat, packed anaerobically, was irradiated at room temperature and in the frozen state with a wide range of doses of 4 MeV cathode rays. Sterility was achieved in 14 out of 15 samples which had received 2 × 10 6 rads or more. Doses of 0·5 and 1·0 × 10 6 rads allowed survival of a few bacteria/g, usually spore formers. Bacterial counts indicated an approximately logarithmic decrease in numbers at lower doses, while freezing reduced the bactericidal effect. The storage life at 5° was prolonged only slightly by doses of 5 × 10 4 and 10 × 10 4 rads, and highly variable results were obtained with 17·5 × 10 4 rads. A dose of 25 × 10 4 rads, however, increased the storage life very considerably. The types of bacteria present initially, and after irradiation with low doses and storage at 5°, were studied. After storage for 12 days or more various types of nonsporing Gram‐positive rods were predominant in almost all samples, both control and irradiated. Streptococci were also important where irradiation with 17·5 × 10 4 and 25 × 10 4 rads was followed by long storage.